Conventionally, there has been known an arc welding (so-called an arc brazing) which generates an arc discharge between a welding torch and base materials, melts a filler wire (brazing filler metal) by high heat of the arc discharge, and fuses the base materials and the brazing filler metal to be mixed at a molecular level. There is an advantage that the base materials can be welded relatively easily even if a joint portion between the base materials is a complicated shape, because the molten brazing filler metal enters a narrow gap of the joint portion by performing the arc welding.
Patent Document 1, for example, discloses a pulse arc welding method in which while generating the arc discharge between the base materials by supplying an arc current in a pulse shape to a non-consumable electrode, the filler wire is intermittently fed to be synchronized with the pulse of the arc current. Note that, in Patent Document 1, it is adopted that the filler wire is melted when a value of the arc current is a peak current (>a base current), and the filler wire is not melted when the value is the base current.